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Title: Optimisation and application of AP MeV SIMS
Author: Matjacic, Lidija
ISNI:       0000 0004 7226 5059
Awarding Body: University of Surrey
Current Institution: University of Surrey
Date of Award: 2018
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Ion beam analysis comprises of a group of analytical techniques tackling the elemental composition of thin films by probing them with MeV ions. These techniques exploit information from photons and particles that come from the interaction of the MeV ions with the sample surface. Secondary ions, yet another species ensuing from such interactions can also be analysed providing information on molecular composition. The only ion beam analysis technique addressing the molecular composition is MeV SIMS, enabling detection and imaging of organic matter. The molecular detection and imaging of organic material is dominated by other surface sensitive techniques, such as TOF SIMS, providing a strong competition to MeV SIMS. In a pursuit to fully exploit the advantages of MeV SIMS in the field, the possibility to extract MeV ions into the air can also be utilised, thus offering the potential for application of ambient based MeV SIMS. In this work, a fully ambient MeV SIMS setup is introduced and commissioned at the University of Surrey Ion Beam Centre, and termed “Ambient Pressure MeV SIMS”. The aims of this thesis are to optimise AP MeV SIMS for detection and imaging of organic species, as well as to explore potential applications for the technique. The complex optimisation of AP MeV SIMS described in this work encounters many parameters influencing either the electronic sputtering or gas dynamic of secondary ions. A great volume of the optimisation process has addressed the issue of an immense background contribution by investigation of its identity and origin. Moreover, the atmosphere encompassing the sampling area was investigated and the effect of different angles and types of a sheath gas directing the sample was tested. The following work of this thesis demonstrates the application assessment of AP MeV SIMS. Here results of analysis of amino acids, explosives and synthetic organic pigments are presented. Finally, a description of a feasibility study on merging of AP MeV SIMS and HIPIXE with a purpose of simultaneous molecular and elemental imaging under ambient conditions is given.
Supervisor: Webb, Roger Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available